Although trailer hitches of the ball and socket type include a jaw pivotable on a horizontal axis for locking the ball to the socket, they are known to disengage during transit. This can have devastating results, ranging from destruction of the trailer and its load to personal injury or death. Should the ball and socket disengage, the trailer is held only by a safety chain. Safety chains and cables are considered necessary because a hitch ball and hitch ball coupler must have universal motion in order for the towing vehicle and trailer to negotiate around curves and over hills, whereupon the longitudinal axes of the towing vehicle and trailer are not aligned and additional vertical and lateral forces might be applied to the trailer hitch. This relative motion between the trailer and the towing vehicle sometimes causes the hitch ball coupler to separate from the hitch ball. Also, there are times when the load carried by the trailer tends to cause the hitch ball coupler to lift upwardly away from the hitch ball, and there are other times when the application of the brakes of the towing vehicle applies so much stress to the hitch ball and hitch ball coupler that separation of the trailer from the towing vehicle becomes more likely. There are many instances where the safety chain is broken and the trailer is released from the tow vehicle. For these reasons, attempts have been made to increase the safety of the trailer hitch.
For example, U.S. Pat. No. 8,444,169 discloses a trailer hitch coupler to couple a trailer to a trailer hitch includes a socket adapted for receiving a trailer hitch ball; a clamp associated with the socket and operable for engaging the trailer hitch ball; a sensor operatively connected with the socket and operable for determining a distance between an inner surface of the socket and an outer face of the trailer hitch ball when the trailer hitch ball is positioned within the socket; a clamp prevention device operatively connected with the socket and with the clamp and operable to prevent engagement of the clamp with the trailer hitch ball; and a release mechanism operatively connected with the sensor and the clamp prevention device and operable to release the clamp prevention device to allow the clamp to engage the trailer hitch ball when the sensor communicates a desired hitch condition. The object of this invention is to provide a sensor to alert a user that the wrong sized socket has been used with the ball. It does not prevent the ball and socket from disengaging and releasing the trailer from the vehicle during transit.
U.S. Pat. No. 7,334,809 discloses a trailer hitch assembly that better secures a trailer to a vehicle trailer hitch. By restricting vertical travel of the trailer coupling, a hitch ball on a draw bar is better engaged by the trailer coupling as any vertical dislodgement of the trailer coupling from the hitch ball is restricted by the underlying trailer hitch assembly. The underlying trailer hitch assembly cannot travel upward when locked into position as the draw bar obstructs its upward travel, thus preventing the trailer coupling from disengaging the hitch ball. The trailer hitch assembly is lockably, pivotable away from the underside of the draw bar in order to allow controlled disengagement of the trailer coupling from the hitch ball. The trailer hitch assembly may act as a support when placed in the vertical or downward position with a wheel, pad, or skid providing support for the accompanying trailer and its load. Additionally, a new trailer hitch ball system is detachably attachable to the draw bar without a shank, nut, or washer. This is simply a dolly wheel and jack that can be used to raise and lower the trailer neck, when the trailer is not being towed. It does not address the problem of the hitch disengaging while the trailer is being towed.
U.S. Pat. No. 6,971,661 discloses a safety cable cartridge 20 that is connected between a towing vehicle 12 having a hitch ball and a trailer 10 including a tubular coupler housing 16 mounted to a trailer draw bar. The cartridge is self contained and includes a cartridge housing 28 for positioning in the elongated opening of the coupler housing, at least one safety cable assembly 30 positioned in said cartridge housing, and spring 20 surrounds the cable 31 and biases the distal end 30 of the cable toward the cartridge housing. This does not stop the hitch ball and socket from disengaging.
U.S. Pat. No. 6,802,523 discloses a safety fastener for ball and socket hitches of medium to heavy vehicles provides a base defining a channel to fit about a hitch tongue beam of a towing vehicle with holes in the base to receive the fastening bolt of a hitch ball to fasten the base and hitch ball on the hitch tongue. The base carries at least one collar for adjustable positioning of at least one vertical fastener arm by a pin fastener. The vertical fastener arm carries a horizontal fastening beam extending over the hitch beam carried by the ball to prevent removal of the hitch from the ball. Species provide one or two vertical fastening arms carrying the fastening beam. The pin fastener may carry a lock to prevent unauthorized removal of the hitch from the ball. A horizontal member is positioned to contact the upper surface of the socket, hence this design would interfere with the rotation of the socket about the ball. Further, the vertical member would limit movement of the tongue of the trailer about the ball, such as would occur during a turn. This design therefore is not for preventing disengagement of the trailer when in transit.
U.S. Pat. No. 6,386,572 discloses a safe and secure trailer hitch for use with a towing vehicle. More particularly, but not by way of limitation, the present invention relates to an optical guiding trailer hitch device which allows an operator of a towing vehicle to easily, accurately, and safely attach a trailer to the towing vehicle. Additionally, the optical guiding trailer hitch device may further include an assembly for aligning the trailer in a horizontal plane relative to the towing vehicle. The present invention in conjunction with a trailer may be used for the transportation of a boat, a camper, a mobile home, or any such object which may be moved from one place to another place using a trailer and a towing vehicle. This does not address the problem of the hitch disengaging while the trailer is being towed.
U.S. Pat. No. 4,593,264 discloses a dual trailer hitch warning system for use with a ball and socket trailer hitch including an electrically operated alarm system for signaling a loose coupling of the socket member on the ball member. A switch is mounted within the ball member which energizes an alarm relay circuit when the ball switch operates due to a loose coupling to complete an alarm circuit between the automobile battery and the horn. The warning system also includes a tampering relay circuit adapted to provide an alarm signal if an attempt is made to disengage or short out the alarm circuit or if the socket and ball member are deliberately uncoupled. This does not address the problem of the hitch disengaging while the trailer is being towed.
U.S. Pat. No. 4,577,884 discloses a device for preventing unauthorized intentional uncoupling or accidental uncoupling of a trailer from a towing vehicle. The threaded shaft of the ball slides through an upper housing allowing the upper housing to contain the shoulder of the ball so that the ball and upper housing can be mounted to a tow bar by inserting the threaded shaft of the tow ball through the aperture in a tow bar and then screwing a flanged nut onto the threaded shaft. A lower housing is then placed around the flanged nut and bolted to the upper housing so that the tow bar and the flanged portion of the flanged nut are sandwiched between the upper and lower housings. There is a yoke which encircles the shank of the tow ball, the dimensions of which make it impossible for it to slide over the ball. There is a locking hat which is placed over the trailer tongue ball socket having legs extending vertically downward allowing it to be locked to the yoke. Once in locked position, the trailer hitch cannot be disengaged without first unlocking and removing the locking hat. Although the locking hat and yoke are purported to not limit the inherent rotation of the socket about the ball, it can be seen from the drawings that they clearly do, hence this would not be suitable for use when towing a trailer.
U.S. Pat. No. 3,759,548 discloses a safety trailer hitch in which a ball is mounted on the towing vehicle and a ball clamping coupling is mounted on the trailing vehicle. A member carrying a finger is arranged on the towing vehicle to be positioned with the finger overlying the coupling to prevent the coupling from detaching from the ball even if unlocked. The finger is mounted to be swung out of the way as required to permit the coupling to be disconnected from the ball. As shown, the finger presses on the upper surface of the socket, holding the socket on the ball. This would impede rotation of the socket relative to the ball. In a modified form of the invention a yoke is mounted on the towing vehicle for swinging to a position overlying the coupling to prevent the coupling from being detached from the ball. This would interfere with the rotation of the ball in the socket when towing a trailer. Further, there may be potential for the socket to jam in the attachment or disengage from the ball as it is urged upward during braking.
U.S. Pat. No. 4,032,171 discloses a theft deterrent trailer hitch lock to obstruct removal of the socket portion of a trailer hitch from engagement with a trailer hitch ball mounted on a tow bar secured to a towing vehicle. The device includes a right angular-shaped base having a first flange underlying the hitch ball and bolted to the tow bar by bolts having an upstanding end portion projecting above the upper limit and on opposing sides of the trailer hitch socket portion. The upstanding flange of the angle base is pivotally connected with a top member vertically movable toward and away from the upper limit of the trailer hitch socket portion and having apertures therein receiving the upper ends of the base flange bolts. A lockable bar, slidably supported by the top member along its edge opposite the pivotal connection, is provided with an aperture mating with an aperture in the top member for receiving the bolt of a lock. This would interfere with the rotation of the ball in the socket when towing a trailer. Further, there may be potential for the socket to jam in the attachment or disengage from the ball as it is urged upward during braking.
U.S. Pat. No. 3,549,173 discloses a safety trailer device having an alternate connection between the motor vehicles and the towed vehicle comprising a channel member with aligned apertures in opposite ends thereof such that a ball connector may be mounted in the lower end and a safety connector may be secured to the other end vertically above the ball connector. It is disclosed that the safety connector is connected directly over the centre of the ball. In one embodiment, an eyebolt is adjustably mounted above the socket to prevent upward movement of the socket a sufficient distance to disengage the ball without removing the eyebolt. As before, this is located directly above the centre of the ball. The deficiency in this design is that a threaded connection as is used for the eyebolt is subject to corrosion, and therefore, would cease to function very quickly if used in salt water. It would also be difficult to feed the socket and tongue under the top member that retains the eyebolt. It would also not be robust enough to withstand the force of the tongue lifting as the bend in the connector is a weak point. Further, there may be potential for the socket to jam in the attachment or disengage from the ball as it is urged upward during braking.
U.S. Pat. No. 3,677,564 discloses a safety trailer hitch in which a yoke is secured to the tow bar of the trailer and to the hitch of the towing vehicle to prevent the trailer from becoming disconnected should the socket portion on the trailer become detached from the ball. The yoke may be easily disconnected from the trailer hitch when disconnecting the trailer from the towing vehicle. In a modified form of the invention a finger on the trailer hitch is arranged to be swung into a position overlying the socket to prevent the socket from detaching from the ball. When disconnecting the trailer the finger is swung out of the way to permit the socket to be lifted off of the ball. The deficiency in this design is that a threaded connection as is used for the finger bolt is subject to corrosion, and therefore, would cease to function very quickly if used in salt water. It does not look as though it would be robust enough to stop the socket from disengaging. Further, there may be potential for the socket to jam in the attachment or disengage from the ball as it is urged upward during braking.
U.S. Pat. No. 4,208,065 discloses a base is secured to a mounting member extending from a towing vehicle and having an upstanding ball element. A retention member carried by the base is selectively movable to a position over a socket element which extends from a towed vehicle and which is detachably engaged downwardly over the ball element. The retention member limits the upward travel of the socket element and maintains engagement of the coupling. The retention member is held in position by lock means. A resilient member is disposed between the base and the retention member to prevent the retention member from rattling against the base. The retention member is hinged to the base. Upward force on the retention member could shear the clevis pins, allowing the trailer to be disengaged. Other disclosed embodiments include a U-shaped member that sits around the ball, and a threaded member that can be wound down onto the socket. This would be difficult to use as there is little space between the top of the U and the ball for placement of the socket. Also, as it is threaded, corrosion could be an issue. Upward force on the retention member could shear the pin, allowing the trailer to be disengaged. Further, there may be potential for the socket to jam in the attachment or disengage from the ball as it is urged upward during braking.
U.S. Pat. No. 5,087,064 discloses an anti-theft, safety device for use with ball and socket trailer hitches comprising a base plate clamped to the tow bar near the ball, a post attached at one end to the base plate that extends vertically from the tow bar adjacent to the ball and socket, an upper plate through which the post extends that moves vertically and rotates with respect to the post, a bushing with an opening in register with the opening in the upper plate through which the post extends, both the post and the bushing having transverse openings through which a lock bolt may be passed when the holes are aligned so that the upper plate will be held over the socket to prevent the socket from being disconnected from the ball. The upper plate is located such that it will interfere with the rotation of the socket in relation to the ball. Further, there may be potential for the socket to jam in the attachment or disengage from the ball as it is urged upward during braking.
A hitch attachment for theft prevention and safety is at http://hitchsafe.com/ This device has a hinged gate that is locked in place overtop the socket once the trailer has been located on the hitch. It requires a padlock to lock it in place. While this may deter thieves, it would not prevent the trailer from detaching in the case of an accident, sudden braking or the like. There is also no consideration of the relation between the hinge attachment and the ball and socket, hence the turning radius may be compromised. Further, there may be potential for the socket to jam in the attachment or disengage from the ball as it is urged upward during braking.
What is needed is a safety device for attachment to a trailer hitch that allows the hitch ball and socket to have unimpeded rotational motion while reducing or eliminating the potential for the hitch ball and socket to disengage. The device would preferably be easy to use and would require little modification to the hitch. It would be preferable if it had few moving parts and was resistant to corrosion. It would be preferable if it did not interfere with the process of attaching the trailer to the hitch. It would be preferable if it could be added to existing trailer hitches, or could be supplied as part of a new hitch assembly. It would be preferable if the device was designed to take into consideration the effect of hard braking on the relationship between the ball and socket, as the socket may become jammed if the tolerances are too small or the socket may still disengage if the tolerances are too large.